Transformation of adult myelodysplastic syndrome-refractory anemia to acute T-cell lymphoblastic leukemia.

OBJECTIVE

Myelodysplastic syndrome (MDS) is recognized as a preleukemic disorder with a variable risk of transformation to acute myeloid leukemia. Usually the blast cells in leukemia are transformed after MDS displays a myeloid phenotype. Lymphoid progression had been reported as myeloid-lymphoid hybrid or early B phenotype, but our patient transformed acute T-lymphoblastic leukemia, which is a rare lymphoid transformation.

CLINICAL PRESENTATION AND INTERVENTION: We present a case of refractory anemia with excess of blast that transformed into acute T-cell lymphoblastic leukemia. MDS was diagnosed in a 69-year-old man in April 2007. Twelve month later, he developed T-acute lymphoblastic leukemia. The blasts were positive for expression of CD2, CD3, CD5, CD7, CD45, and HLA-DR, leading to a diagnosis of T-lymphoblastic leukemia. The patient was treated with chemotherapy, but he died of multiple organ failure.

CONCLUSION

The mechanism of lymphoid transformation is not yet fully understood. This case clinically supports the nature of MDS as a pluripotent hematopoietic stem cell disorder. MDS often transforms into acute leukemia, usually of a myeloid phenotype. The transformation of MDS into acute lymphoblastic leukemia is extremely rare.